Windows

Windows NT creates hidden shares of all local hard drives each time the system boots,these Administrative are only for users with administrative priviliges can access them.They are used to guarantee access to drives in the event that stanard ACL permissions for the system prevent authorized access
Can be viewed through Server Mnanger
To disable>HKEY_LOCAL_MACHINE\System\Current\ControlSet\Services\LanManServer\Parameters Registry key
Avalue of 0 disables;value of 1turns on

The way Arcserve displays this info is a little confusing, but what it does, if I remember correctly, is this: if you expand the tree listing under the administrative shares - C$, D$, etc., what you see is all the directories that you would normally see if you were looking directly at the drive through Explorer (i.e., the full contents of the drive). If you expand the tree under the plain drive letter - C, D, etc. - what you see is the shared directories only. So, if you have a directory on the C drive called Documents and it is shared with the share name Public Docs, under C$ you see Documents, under C you would see Public Docs.. Hope this helps!

Basically that first list that shows up are all of the shared folders on that server. The C$ and D$ shares are made automatically by the system. The other listing for D is more than likely a copy of the D$ that someone made manually for those users who do not have administrative access. You may want to check the permissions for that share. If it is set to Everyone full control or anything similar, find out who is accessing it through Server Manager. You will probably want to get rid of it.